I'm sure this is commonplace, and I hesitate to admit to an interest in
exotics, but maybe someone can enlighten me.
Outside my office there is a moat with (among other things) a pair of
Mallard (Anas platyrhnchos) and an attendant white domestic duck. The three
have been inseparable for at least 4 months. During the breeding period the
two mallard were in male breeding plumage - glossy green head, white
ring around neck, chestnut breast etc - but one with the regulation yellow
bill, one with a grey bill. At the end of the season both reverted to brown
mottled eclipse plumage.
During the breeding season, the grey-billed male assumed the role of
shepherding the other male Mallard, as though the latter were a female,
constantly manouvering to be between the 'female' and the white duck
(all day every day, it must have been exhausting). On the rare occasions
his guard dropped, even for a second, the white duck rushed in and
copulated with the 'female', oblivious to the savaging the 'male' was
delivering to his body at the time.
This seemed odd, too, because I thought that breeding Mallard pairs were
quite aggressive to other Mallard (although in this case I guess the third
party was a "Mallard"). Certainly the three of them spent a lot of time
together trying to drive away the Pacific Blacks, although they usually
ignored the Wood Duck.
The three are still inseparable and seem to get on famously. What's going